Nova Company$$s total overhead cost at various levels of activity are presented below:

Month Machine$-$Hours Total Overhead Cost

April $48,000$ $ $180,860$

May $38,000$ $ $155,660$

June $58,000$ $ $206,060$

July $68,000$ $ $231,260$

Assume the total overhead cost above consists of utilities, supervisory salaries, and maintenance. The breakdown of these costs at the $38,000$ machine$-$hour level of activity is:

Utilities $($variable$)$ $ $49,400$

Supervisory salaries $($fixed$)40,000$

Maintenance $($mixed$)66,260$

Total overhead cost $ $155,660$

Nova Company$$s management wants to break down the maintenance cost into its variable and fixed cost elements.

Required:

Estimate how much of the $$231,260$ of overhead cost in July was maintenance cost. $($Hint: To do this, it may be helpful to first determine how much of the $$231,260$ consisted of utilities and supervisory salaries. Think about the behavior of variable and fixed costs.$)$

Using the high$-$low method, estimate a cost formula for maintenance in the form Y $=$ a $+$ bX$.$

Express the company$$s total overhead cost in the form Y $=$ a $+$ bX$.$

What total overhead cost would you expect at an activity level of $43,000$ machine$-$hours?